1. Field of the Invention:
The invention in general relates to inductors, and particularly to those having extremely large structures capable of handling ultra-high currents.
2. Description of the Prior Art:
High energy inductors are utilized in a variety of pulsed power applications wherein the inductor is utilized as an intermediate pulse compression device. By way of example, relatively large inductors for magnetic energy storage for pulse power find application in the field of electromagnetic launchers which require pulsed power supplies capable of providing megampere currents at kilovolt levels for times of several milliseconds. This current level is needed in order to launch a projectile along parallel conducting rails such that the projectile has an exit velocity of many kilometers per second.
For some applications, inductors made with superconducting coils may be utilized under conditions where volume and space constraints are of no concern. The short energy storage times typical in the electromagnetic launcher system, however, would allow the use of non-superconducting technology without severe energy loss penalties. Additionally, the megamp current requirements for the electromagnetic launcher make the use of superconducting coils less attractive.
The requirements of a typical electromagnetic launcher system dictate that stray magnetic fields be limited, and accordingly use is made of toroidal coil geometries. One typical inductor which meets this requirement is fabricated from a plurality of rugged copper coils constructed of solid copper plates arranged in a circular array. The relatively simple and rugged construction of such inductor insures that it holds up well under repeated mechanical stress generated with pulse power applications, however, the efficiency is somewhat limited due to the current concentrations near the magnetic bore which tend to increase the effective resistance of the unit and thereby decrease its efficiency. Additionally, only a single inductance value is possible with such construction.
The inductor of the present invention exhibits relatively high efficiency and is capable of repeatedly carrying high currents in the order of millions of amperes. The inductor is of toroidal design to minimize external fields and is capable of being connected in two different inductance value configurations.